Magnesium implants were clinically used for the treatment of bone fractures by several surgeons back in the 1930s. For instance, J. Verbrugge (1934) used both pure magnesium and Mg-8% Al alloy implants on 21 patients. However, after the Second World War, the use of magnesium as a resorbable implant material fell into oblivion. In recent years, researchers have renewed their interest in resorbable magnesium implants. A main focus of magnesium research is the development of alloys and coatings. The major goals are to control the degradation rate, to avoid the formation of gas bubbles during degradation and to avoid potentially harmful alloying elements. Therefore, a need exists for magnesium alloys with a homogenous degradation behavior whose rate of degradation can be controlled and/or tuned as desired.
Commercial grade pure magnesium (3N—Mg) has poor mechanical properties in comparison with alloys like AZ91 or WE43. The possibilities to harden pure magnesium are quite limited. Hardening might be achieved by refining the grain microstructure using plastic deformation to induce dynamic recrystallization (e.g. by extrusion). The fine grained microstructure is not only necessary to achieve a better strength level but also needed to avoid mechanical anisotropy (strength difference between tension and compression). The microstructure might not be stable, though.
Embodiments of the present invention overcome one or more of above-noted challenges.